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2 resultados encontrados para: AUTOR: Valencia Quintana, R.
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Resumen en: Inglés |
Resumen en inglés

The objective of this study was to determine methane (CH4) yield by crossbred cattle fed tropical grasses. A total of 66 individual determinations of dry matter intake (DMI) and 42 determinations of organic matter intake (OMI) in relation to the production of enteric CH4 were carried out. Methane measurements in heifers were performed in open-circuit respiration chambers. Heifers (Bos indicus×B. taurus) with an average live weight of 288.5 ± 55.7 kg fed tropical grasses as basal ration were used. An average intake of 8.22 and 7.80 kg of DM and OM per day were recorded. An average enteric CH4 production of 88.0 g/heifer/day was determined. It was found that DMI and OMI in relation to CH4 production have a coefficient of determination (R²) of 0.73 and 0.70 respectively, to predict CH4 emissions. It is concluded that the methane yield (18.07 g CH4/kg DM intake) predicted by regressing DM intake against methane production represents a reliable value to be used for the estimation of enteric CH4 inventories for cattle grazing in the tropical regions of Mexico.


2.
Artículo
Descripción de la concentración de sólidos en el río Zahuapan, México
Muñoz Nava, Hipólito (coaut.) ; Sedeño Torres, E. (coaut.) ; Goméz Camarillo, M. (coaut.) ; Suárez Sánchez, Juan (coaut.) ; Van Der Wal, Hans (coaut.) ; Valencia Quintana, R. (coaut.) ; Juárez Santacruz, Libertad (coaut.) ;
Contenido en: Gestión Ambiental No. 33 (2017), p. 63-76 ISSN: 0718-445X
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
43123-10 (Disponible)
Disponibles para prestamo: 1
Resumen en español

El río Zahuapan está afectado por las actividades antrópicas. El objetivo fue describir temporal y espacialmente la concentración de sólidos: totales, flujos, volátiles, suspendidos, y disueltos. Se utilizaron datos de estos contaminantes de 2000 a 2014. La descripción temporal se realizó anual y mensualmente, y espacial con base en las áreas de captación (microcuencas) de los afluentes del río. Como una forma de identificar semejanzas entre las microcuencas y encontrar posibles asociaciones entre ellas, se realizó análisis factorial exploratorio. Los resultados mostraron que en el río predominaron los sólidos flujos y en menor medida los volátiles. En la mayoría de los años considerados, las concentraciones de sólidos superaron o estuvieron alrededor de los límites máximos, exceptuando los sólidos volátiles. Los sólidos totales, flujos, suspendidos y disueltos mostraron una variación estacional influenciada por la temporada de lluvias. Se identificaron 12 microcuencas y éstas tuvieron un efecto aditivo sobre la concentración de sólidos. El análisis factorial mostró que las microcuencas fueron diferentes y deben ser consideradas como unidades independientes en las acciones de saneamiento del río Zahuapan.

Resumen en inglés

Zahuapan River is affected by anthropic activities. The goal of this study was to describe temporal and spatially the solids concentration: total, fixed, volatile, suspended and dissolved. Data of those pollutants were used from 2000 to 2014. The temporal description was made annually and monthly, and spatially description was made on the base of watershed (microbasins) tributaries of the river. In order to identify likeness between microbasins and fi nd out possible associations, the exploratory factorial analysis was made. Results showed that fixed solids were predominant, and volatile solids lesser extent. The bulk of them considered year, solids concentrations were greater than or around of ceilings, excepting volatil solids. Total, fixed, suspended, and dissolved solids showed seasonal variation due by rainfall. 12 microbasins were identified; they had an additive effect on solids concentration. Factorial analysis showed that microbasins were different, and they must be considered as independent units in actions to reclaim Zahuapan River.